Respiration humidifiers are used to humidify the inspiratory gas of respirators to physiological levels.
The upper airway of a patient normally warms and humidifies the inspired gases during normal breathing. However, this is compromised when inspired gas is delivered by invasive or non-invasive ventilator. During invasive ventilation, the use of endotracheal tube bypasses the upper airway and so upper airways cannot contribute to heating and humidification of the delivered gases. This may lead to bronchial inflammation and related respiratory complications. During non-invasive ventilation, the nasal mucosa may not be able to adequately warm and humidify the inspired gas and can lead to thick mucus leading to increase in airway resistance and reduced lung compliance.
Hence in clinical practice, humidifiers are used to provide adequate heat and humidification to the delivered gas.
Generally humidifiers are rather bulky, heavy and may be characterized by a high degree of heat loss.
Humidifiers, such as heat and moisture exchangers (HME), also referred to as passive humidifiers may not be able to reliably maintain the temperature and humidity for high flow of inspired gas as humidity is usually maintained by the exhaled air. In contrast, heated humidifiers (HH), also referred to as active humidifiers try to maintain the temperature and humidity of delivered gas by controlling a heating plate that heats and evaporates the water in path of gas flow. However, these humidifiers introduce additional dead space or additional resistance in the circuit, or may have to be changed daily as for HMEs to avoid bacterial contamination, or cannot reliably deliver heated and humidified gas.
Such devices, which operate according to various principles, are arranged, in general, separated from the respirator.
One drawback of the separate arrangement for the user is, among other things, the large number of different tubing and connections.
Another drawback of the current humidifiers is that, during the transport of the patient, they need to be switched off and disconnected and thus switched to passive humidification.
Hence, an improved humidifier would be advantageous, and in particular a humidifier for use in a patient ventilation circuit, which can be integrated within a respirator, would be advantageous.
Furthermore, efficient humidifier would be advantageous, and in particular a humidifier for use in a patient ventilation circuit, which can continue active humidification during the transport of the patient, would be advantageous.
A low cost, lightweight humidifier would also be advantageous, and in particular a humidifier for use in a patient ventilation circuit, which has a fast response rate, would be advantageous.
An improved humidifier would also be advantageous, and in particular a more efficient and compact humidifier for use in a patient ventilation circuit would be advantageous.